5237 Author Almeida, Nadiny Martins De Author Ferreira, Vitor Góis Author Martens, Koen Author Higuti, Janet text Zootaxa 2023 2023-02-07 5237 1 88 journal article 54754 10.11646/ZOOTAXA.5237.1.1 eb843022-9cfd-4df9-a3ea-c022ab89528e 1175­5334 7640078 3A5A9DF9-763E-4561-AC62-7E0D2F0B54B4 Brasilocypria pea gen. et spec. nov. ( Figs 3–15 ) 2009 Physocypria sp. 2 n.sp. Higuti et al. : table 1. 2010 Physocypria sp. 2 n.sp. Higuti et al. : table 2. 2015a? Physocypria sp. 2 n.sp. Matsuda et al. : 326, table 1. 2015b? Physocypria sp. 2 n.sp. Matsuda et al. : 118, 122, table 1, fig. 5. 2017? Physocypria sp. 2 n.sp. Campos et al. : 38, table 2. 2018? Physocypria sp. 2 n.sp. Conceiç„o et al. : table S1. 2017a? Physocypria sp. 1 Higuti et al. : 327, table 2. 2017b? Physocypria sp. 2 n.sp. Higuti et al. : 5, appendix 1. 2018? Physocypria sp. 1 n.sp Campos et al. : 6, table 2. 2019? Physocypria sp. 1 Campos et al. : 375, table 1. Diagnosis . Cp with suboval shape, LV overlapping RV along all valve margins, except along posterior part of dorsal margin; anterior overlap the widest. Posterior marginal tubercles on RV more prominent than anterior ones. A2 with five well-developed and long natatory setae, short accompanying seta missing. A 2 in male with foursegmented endopodite and with t2 and t3 transformed into sexual bristles. Rpp and Lpp asymmetrical. Rpp with first segment narrow and elongate, distal edge moderately pointed. Lpp with first segment equally elongated; second segment sickle shaped, narrow. T1 with one long and hirsute seta next to the two a-setae. T2 without setae d1 and d2. T3 without d2-seta. CR with a long proximal seta. Hp with ls long and narrow, ms triangular, reaching about halfway ls. Differential diagnosis . Brasilocypria pea gen. et spec. nov. can be distinguished from other Physocypria s.l. species by the moderate dorsal expansion on the RV. Physocypria gibbera ( Furtos, 1936a ) , Physocypria inflata Furtos, 1933 and Physocypria pustulosa ( Sharpe, 1897 ) have much larger dorsal expansions of the RV. Brasilocypria pea gen. et spec. nov. is somewhat similar to Keysercypria schubarti ( Farkas, 1958 ) , with the ls of the Hp being almost twice the length of the ms, while the ms is also pointed. These two species mainly differ in the morphology of the Cp, where K. schubarti has a much larger anterior overlap of the LV over the RV. Furthermore, the Rpp and Lpp in K. schubarti are smaller and more robust, while in B. pea gen. et spec. nov. the Rpp is much more elongated than the Lpp. Finally, K. schubarti also has a very long h3-seta on T2, typical of Keysercypria (see Discussion). Brasilocypria pea gen. et spec. nov. is differentiated by the dorsal margin on RV, which is more rounded in this species and straighter in B. ricardopintoi gen. et spec. nov. and B. lordi gen. et spec. nov. Also, the overlap of LV on RV in B. pea gen. et spec. nov. is more prominent, as in B. ricardopintoi gen. et spec. nov. . Material examined. Type locality: Upper Paraná River floodplain, Aurélio Lake ( PAR 150 ), in floating macrophytes. Coordinates : 22°41′36.5′′ S , 53°13′52′′ W . Type material: Holotype : A male , with soft parts dissected in glycerine in a sealed slide and with valves stored dry in a micropaleontological slide ( MZUSP 43091 ). Allotype: A female , dissected and stored as the holotype ( MZUSP 43092 ). Paratypes : Two males dissected and stored as the holotype ( MZUSP 43093 , MZUSP 43094 ) . Three male carapaces stored dry in micropaleontological slides ( MZUSP 43095 , MZUSP 43096 , MZUSP 43097 ) . Two females dissected and stored as the holotype ( MZUSP 43098 , MZUSP 43099 ). One female carapace stored dry in a micropaleontological slide ( MZUSP 43100 ) . Etymology: This species is named after the Graduate Program in Ecology of Inland Water Ecosystems (Programa de Pós-Graduaç„o em Ecologia de Ambientes Aquáticos Continentais—PEA) of the State University of Maringá ( Paraná , Brazil ), on the occasion of its 30 years of existence. Other material illustrated: Upper Paraná River floodplain: Two female carapaces stored dry in micropaleontological slides (both Cp lost after use for SEM) from Aurélio Lake (PAR 150). South Matogrossense Pantanal : One male dissected and stored as the holotype ( MZUSP 43101 ) . Three male carapaces stored dry in micropaleontological slides ( MZUSP 43102 , MZUSP 43103 , MZUSP 43104 ) from Carenda Forest Road, lake 1 (PAN 09) . One female dissected and stored as the holotype ( MZUSP 43105 ) . Three female carapaces stored dry in micropaleontological slides ( MZUSP 43106 , MZUSP 43107 , MZUSP 43108 ) from Carenda Forest Road, lake 1 (PAN 09) . Other material examined: Upper Paraná River floodplain: Two males dissected and stored as the holotype ( NA116 , NA119 ) from Aurélio Lake (PAR 1631) . South Matogrossense Pantanal : One male dissected and stored as the holotype ( MZUSP 43109 ) from Carenda Forest Road , lake 1 (PAN 09) . One female dissected and stored as the holotype ( MZUSP 43110 ) from Carenda Forest Road , lake 1 (PAN 09) . Measurements of illustrated specimens . See Table 2 . Description of male . Valves with suboval shape, with greatest height just behind the middle of the valves. LVi ( Figs 3A, C–D ) with narrow calcified anterior and posterior inner lamella; an inwardly displaced inner list running along the anterior margin, ending in an internal anteroventral tooth; tubercle-sockets displaced along anteroventral and posteroventral margins. RVi ( Figs 3B, E–F ) with narrow calcified anterior and posterior inner lamella and an inwardly displaced inner list along the anterior margin, disappearing in the middle; strong marginal tubercles along the anteroventral and posteroventral margins, weakly along the ventral margin. CpRl ( Fig 3G ) with a suboval shape, with greatest height in the middle; LV overlapping RV along all margins, except in the middle of the dorsal side. CpD ( Fig 3H ) and CpV ( Fig 3I ) with greatest width slightly behind the middle, external surface set with few short setae and shallow pits ( Fig 3J ). A1 ( Fig 4A ) with seven segments. First segment large, with two long hirsute ventro-apical setae; one short hirsute dorsal seta; Wouter’s organ not seen. Second segment wider than long, with one short hirsute dorsal seta; Rome organ not seen. Third segment with two apical setae: ventrally with one short seta reaching middle of fifth segment and dorsally with one long hirsute seta reaching beyond middle of terminal segment. Fourth segment with two long dorso-apical setae and two unequally short ventro-apical setae. Fifth segment with four apical setae: two long dorsal ones reaching beyond tip of terminal segment and two ventral, ca. 2x length of fifth segment. Sixth segment with four long apical setae and one short hirsute seta (4x length of terminal segment). Terminal segment with two long setae, one short aesthetasc Ya and one short hirsute seta, the latter twice length of aesthetasc Ya. A2 ( Fig 4B–C ) with protopodite, exopodite and four-segmented endopodite. Protopodite ventrally with three setae: two short setae and one long apical hirsute seta reaching tip of end claws. Exopodite a small plate with one long hirsute seta (slightly longer than first endopodite) and two shorter, unequally long setae (long one ca. 3x length of short one). First endopodal segment ventrally with aesthetasc Y (ca. 1/2 length of segment), one long ventroapical hirsute seta (reaching beyond tip of terminal segment), and five natatory setae, reaching well beyond tip of end claws; short accompanying seta missing. Second endopodal segment with four t-setae of unequal length (t1 long and hirsute, t2 and t3 stout and t4 short); dorsally with two unequally short setae; ventrally with aesthetasc y1 (same length of second endopodal segment) and aesthetasc y2 (reaching middle of terminal segment). Third endopodal segment apically with four claws (G1, G2, z1, z2) and two setae (G3, z3). Terminal segment ( Fig 4C ) with two claws, one long (GM) and one slightly short (Gm) claw, aesthetasc y3 with accompanying seta (ca. 3x length of aesthetasc y3) and g-seta, ca. 2/3 length of y3. TABLE 2. Measurements of the illustrated specimens of the new species and genera. CD = Curva Doleque Road, lake 4; CF= Carenda Forest Road, lake 1; CaR = Camp Road, pool 4; CoR = Corumba Road, lake 4.

Species	Floodplain	Locality name	Sample number	Sex	Slide	V/Cp	L (µm)	H (µm)	W (µm)
B. pea gen. et spec. nov.	Paraná	Aurélio Lake	PAR 150	♁	MZUSP 43091	LV	445	321.7
RV	436.7	310.8
MZUSP 43093	LV	484.2	316.7
RV	474.2	317.6
MZUSP 43094	LV	476.7	310
RV	464.2	318.4
MZUSP 43097	CpRl	485.8	313.3
MZUSP 43096	CpD	477.5	265.9
MZUSP 43097	CpV	485.8	282.5
♀	MZUSP 43092	LV	566.7	394.2
RV	544.2	394.2
MZUSP 43098	LV	543.3	401.7
RV	533.3	391.7
MZUSP 43099	LV	551.7	399.2
RV	534.2	390.1
MZUSP 43100	CpRl	550.8	402.5
Cp lost	CpD	555.8	335.8
Cp lost	CpV	562.5	350.9
B. pea gen. et spec. nov.	South Matogrossense Pantanal	CF	PAN 09	♁	MZUSP 43101	LV	483.3	335.9
RV	467.5	320.1
MZUSP 43109	LV	485.8	339.2
RV	469.2	325.8
MZUSP 43102	CpRl	486.7	325.8
MZUSP 43103	CpD	490	272.5
MZUSP 43104	CpV	502.5	279.2

......continued on the next page TABLE 2. (Continued)

Species	Floodplain	Locality name	Sample number	Sex	Slide	V/Cp	L (µm)	H (µm)	W (µm)
♀	MZUSP 43105	LV	568.3	392.5
RV	553.3	395.8
MZUSP 43110	LV	572.5	399.2
RV	552.5	392.5
MZUSP 43106	CpRl	568.3	388.4
MZUSP 43107	CpD	549.2	325
MZUSP 43108	CpV	540.8	325.5
B. ricardopintoi gen. et spec. nov.	Paraná	Banhado Lake	PAR 255	♁	MZUSP 43111	LV	468.3	282.5
RV	448.3	291.7
MZUSP 43115	CpRl	469.2	292.6
MZUSP 43116	CpD	455	205.8
MZUSP 43117	CpV	453.3	212.5
♀	MZUSP 43112	LV	590	390
RV	571.7	389.2
MZUSP 43120	CpRl	552.5	361.7
MZUSP 43121	CpD	574.2	297.5
MZUSP 43122	CpV	569.2	298.3
B. alisonae gen. et spec. nov.	South Matogrossense Pantanal	Miranda II River	PAN 66	♁	MZUSP 43123	LV	395	265.8
RV	385.8	265.7
MZUSP 43127	CpRl	398	259
MZUSP 43128	CpD	402	228
CpV	402	233.3
MZUSP 43124	LV	455	300
RV	438.3	308.3
MZUSP 43130	CpRl	457	313

......continued on the next page TABLE 2. (Continued)

Species	Floodplain	Locality name	Sample number	Sex	Slide	V/Cp	L (µm)	H (µm)	W (µm)
MZUSP 43131	CpD	478	291
MZUSP 4313	CpV	467	278
B. alisonae gen. et spec. nov.	South Matogrossense Pantanal	CaR	PAN 31	♁	MZUSP 43136	LV	432.5	292.5
RV	420.8	283.3
MZUSP43137	CpRl	447.5	283.3
MZUSP 43138	CpD	448.3	248.3
MZUSP 43139	CpV	440	252.5
♀	MZUSP 43140	LV	504.2	367.5
RV	491.7	355.8
MZUSP 43141	CpRl	488.3	328.3
CpD	489.2	286.7
CpV	493.3	293.4
B . alisonae gen. et spec. nov.	South Matogrossense Pantanal	CD	PAN 08	♁	MZUSP 43133	LV	403.3	289.2
RV	396.7	278.3
B . alisonae gen. et spec. nov.	South Matogrossense Pantanal	CoR	PAN 18	♁	MZUSP 43135	LV	440.8	299.2
RV	423.4	284.2
B. lordi gen. et spec. nov.	Amazon	Manacapuru Lake	AMA 38	♁	MZUSP 43149	LV	537.5	352.5
RV	529.2	344.2
MZUSP 43153	CpRl	553.3	339.2
MZUSP 43154	CpD	531.7	245.8
MZUSP 43155	CpV	545.8	242.5
♀	MZUSP 43150	LV	645.8	388.3
RV	616.7	379.2
MZUSP 43157	CpRl	640.8	409.2
CpD	640.8	318.3

......continued on the next page TABLE 2. (Continued)

Species	Floodplain	Locality name	Sample number	Sex	Slide	V/Cp	L (µm)	H (µm)	W (µm)
CpV	639.2	317.5
B. lordi gen. et spec. nov.	Amazon	Castanho Lake	AMA 80	♁	MZUSP 43166	LV	540	283.4
RV	522.5	315
♀	MZUSP 43167	LV
RV
B. lordi gen. et spec. nov.	Amazon	Cadete Lake	AMA 23	♁	MZUSP 43158	LV	552	313
RV	541	335
MZUSP 43159	CpRl	530	332
MZUSP 43160	CpD	538	222
MZUSP 43161	CpV	518	229
♀	MZUSP 43162	LV	698	428
RV	690	443
MZUSP 43163	CpRl	629	398
MZUSP 43164	CpD	627	325
CpV	632	322
B. nami o tkoi gen. et spec. nov.	Amazon	Castanho Lake	AMA 80	♁	MZUSP 43178	LV	518.3	271.7
RV	490	284.2
MZUSP 43180	CpRl	470	265.8
CpD	466.7	197.5
CpV	458.3	205.8
♀	MZUSP 43179	LV	504.2	336.7
RV	490	342.5
MZUSP 43181	CpRl	486.7	332.5
MZUSP 43182	CpD	493.3	273.3
MZUSP 43183	CpV	481.7	278.3

......continued on the next page TABLE 2. (Continued)

Species	Floodplain	Locality name	Sample number	Sex	Slide	V/Cp	L (µm)	H (µm)	W (µm)
C. mesquitai gen. et spec. nov.	South Matogrossense Pantanal	CF	PAN 09	♁	MZUSP 43184	LV	586.7	387.5
RV	580	403.3
MZUSP 43188	CpRl	613.4	395
MZUSP 43189	CpD	586.7	300
MZUSP 43190	CpV	580	306.7
♀	MZUSP 43185	LV	609.8	481.7
RV	648.3	456.7
MZUSP 43192	CpRl	658.3	427.5
MZUSP 43193	CpD	649.2	367.5
MZUSP 43194	CpV	686.7	390
C. rochei gen. et spec. nov.	South Matogrossense Pantanal	CaR	PAN 31	♁	MZUSP 43195	LV	666.7	446.7
RV	643.3	428.4
MZUSP 43200	CpRl	657.5	406.7
CpD	658.3	323.3
CpV	653.3	330.9
♀	MZUSP 43196	LV	710.8	473.3
RV	695.8	485
MZUSP 43203	CpRl	727.5	515.8
MZUSP 43204	CpD	753.3	410
MZUSP 43205	CpV	704.2	392.5

FIGURE 3. Brasilocypria pea gen. et spec. nov. ♁ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . LVi (MZUSP 43091). B . RVi (MZUSP 43091). C . LVi, detail of posterior part (MZUSP 43091). D . LVi, detail of anterior part (MZUSP 43091). E . RVi, detail of anterior part (MZUSP 43091). F . RVi, detail of posterior part (MZUSP 43091). G . CpRl (MZUSP 43097). H . CpD (MZUSP 43096). I . CpV (MZUSP 43097). J . CpV, detail of anterior part showing the surface of Cp (MZUSP 43097). Scale bars: A–B, G–I = 250 μm; C–F, J = 100 μm. Arrow indicates anterior direction. B, D, F, H arrow indicates piths fitting teeth in opposing valve. FIGURE 4. Brasilocypria pea gen. et spec. nov. ♁ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . A1 (MZUSP 43091). B . A2, without the terminal segment (MZUSP 43091). C . A2, terminal segment (MZUSP 43091). D . Md-coxa (MZUSP 43091). Scale bars: 50 μm. Md-palp ( Fig 5A ) with four segments. First segment with two long plumose setae (S 1 and S 2 ), one long smooth seta and short slender smooth α-seta. Second segment with two dorsal, unequally short setae; ventrally with stout hirsute β-seta (ca. 2/3 length of third segment) and four long setae (three hirsute and one smooth). Third segment with three groups of setae: one dorsal group of four setae (three unequally long and one short ca. 1/4 length of longest); lateral apical γ-seta (1/2 length of terminal segment) and three smooth short setae; one ventral group with one long seta slightly longer than the terminal segment, and one very short seta. Terminal segment with L ca. 3x basal width, with three unequally long claws and two short setae. Md-coxa ( Fig 4D ) elongated, dorsally with a short seta, and with strong and apical teeth, interspaced with some setae. Mx1 ( Fig 5B —chaetotaxy not complete) consisting of three masticatory lobes (endites), a two-segmented palp and a large branchial plate (not illustrated). Branchial plate elongated, with ca. 16 respiratory rays, some quite short, others longer. First segment of palp with five unequally short setae and one stout plumose seta at base of segment. Terminal segment of palp rectangular, ca. half the length of first segment of palp, apically with three claws and two setae (one long 2/3 length of claws, and one short 1/3 length claws). Third and second endites with two smooth claws. First endite short with two basal setae (one short and one long, about 4x length of short one). T1 with protopodite ( Fig 6A ) and endopodite (asymmetrical prehensile palps) ( Figs 6B–C ). Protopodite apically with a group of 12 unequal and hirsute setae, two short smooth a-setae, one short smooth b-seta, one long and smooth d-seta (ca. 3x length of b-seta), and one long and hirsute seta next to two a-setae (almost 3x length of d-seta). Rpp ( Fig 6B ) first segment very elongated, distal margin with a small subtriangular protrusion and one subapical spine; second segment with triangular lobe and concave distal margin. Lpp ( Fig 6C ) with first segment shorter and smaller than Rpp, with one long subapical spine; second segment small, narrow and sickle-shaped, with pointed distal part. T2 ( Fig 5C ) with protopodite, including “knee”-segment and four endopodite segments. Protopodal segment without d1-seta. “Knee”-segment without d2-seta. First endopodal segment with one apical hirsute e-seta, reaching tip of second endopodal segment. Second endopodal segment with one apical hirsute f-seta, reaching beyond middle of third endopodal segment. Third endopodal segment with one subapical hirsute g-seta, reaching the tip of terminal segment, and one accompanying shorter seta. Terminal segment with hirsute setae h1 and h3, the latter longer than h1, and apically a long and serrated h2-claw (ca. 2/3 the length of this segment). T3 ( Fig 6E ) with four segments. First segment with one long and hirsute dp-seta and one short hirsute d1-seta (the latter ca. 1/2 the length of dp), d2-seta absent. Second segment with one very short subapical e-seta. Third segment with two very short setae: medially f-seta and subapically g-seta. Terminal segment short, longer than wide, with three hirsute setae: one short h1-seta, one h2-seta more than twice the length of h1 and one long h3-seta, about as long as T3. CR ( Fig 6F ) well-developed and robust, with proximal Sp-seta of medium length (ca. 1/2 length of ramus), subapically with one serrated Gp-claw, apically with long serrated Ga-claw and short and smooth Sa-seta. CR attachment ( Fig 6G ) robust, with two branches: db short with a rounded protrusion distally and vb longer than db and without a protrusion. Zenker’s organ ( Fig 6D ) about 3x longer than wide, with ca. 5 spiny whorls. Hp ( Fig 6H ) with ls-lobe elongated, ms-lobe short (ca. 1/3 length of the ms-lobe), subtriangular, with pointed tip. Description of female . Valves with suboval shape, with greatest height slightly behind middle of valves. LVi ( Figs 7A, C–D ) higher than male, with narrow calcified anterior and posterior inner lamella, with an inner list running along anterior margin, disappearing in an anteroventral internal tooth; tubercle-sockets displaced along anteroventral and posteroventral margins. RVi ( Figs 7B, E–F ) higher than male, with narrow calcified anterior and posterior inner lamella and an inwardly displaced inner list along the anterior margin, disappearing in the middle; strong marginal tubercles along the anteroventral and posteroventral margins, weakly along the ventral margin; central muscle scars consisting of an anterior row of three elongated scars and one rounded posterior scar ( Fig 7J ); CpRl ( Fig 7G ) with suboval shape, with greatest height in the middle; LV overlapping RV along all margins, except in middle of dorsal side. CpD ( Fig 7H ) and CpV ( Fig 7I ) wider than male, with greatest width behind the middle. FIGURE 5. Brasilocypria pea gen. et spec. nov. ♁ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . Md-palp (MZUSP 43091). B . Mx1 (MZUSP 43091). C . T2 (MZUSP 43091). Scale bars: A–C = 50 μm. FIGURE 6. Brasilocypria pea gen. et spec. nov. ♁ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . T1 (MZUSP 43091). B . Rpp (MZUSP 43091). C . Lpp (MZUSP 43091). D . Zenker’s organ (MZUSP 43091). E . T3 (MZUSP 43091). F . CR (MZUSP 43091). G . CR attachment (MZUSP 43091). H . Hp (MZUSP 43091). Scale bars: A–H = 50 μm. FIGURE 7. Brasilocypria pea gen. et spec. nov. ♀ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . LVi (MZUSP 43092). B . RVi (MZUSP 43092). C . LVi, detail of posterior part (MZUSP 43092). D . LVi, detail of anterior part (MZUSP 43092). E . RVi, detail of anterior part (MZUSP 43092). F . RVi, detail of posterior part (MZUSP 43092). G . CpRl (MZUSP 43100). H . CpD (Cp lost). I . CpV (Cp lost). J . RVi, detail of muscle scars (MZUSP 43092). Scale bars: A–B, G–J = 250 μm; C–F = 200 μm. Arrow indicates anterior direction. FIGURE 8. Brasilocypria pea gen. et spec. nov. ♀ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . A1 (MZUSP 43092). B . A2, without the terminal segment (MZUSP 43092). C . A2, terminal segment (MZUSP 43092). D . Md-coxa (MZUSP 43092). Scale bars: A–D = 50 μm. A1 ( Fig 8A ) with seven segments. First segment large, with two long ventro-apical hirsute setae and one short dorsal hirsute seta; Wouter’s organ not seen. Second segment wider than long, with one short hirsute dorsal seta; Rome organ not seen. Third segment with two apical setae: ventrally with one short seta reaching beyond middle of fifth segment and dorsally with one long seta reaching tip of sixth segment. Fourth segment with two long dorsoapical setae and two unequally short ventro-apical setae. Fifth segment with four apical setae: two long dorsal reaching beyond tip of terminal segment and two ventral twice length of fifth segment. Sixth segment with four long apical setae and one short hirsute seta (3x length of terminal segment). Terminal segment with two long setae, a short aesthetasc Ya and one short hirsute seta, the latter twice length of aesthetasc Ya. A2 ( Fig 8B–C ) with protopodite, exopodite and three-segmented endopodite. Protopodite ventrally with three setae: two short setae and one long apical hirsute seta reaching beyond tip of end claws. Exopodite a small plate with one long hirsute seta (reaching tip of terminal segment) and two unequally short setae (long one ca. 3x length of short one). First endopodal segment ventrally with aesthetasc Y (ca. 1/2 length of segment), one long ventro-apical hirsute seta (reaching beyond tip of terminal segment), and five long natatory setae, reaching well beyond tip of end claws; short accompanying seta absent. Second endopodal segment with four t-setae of unequally length (t1, t2 and t3 long and t4 very short); dorsally with two unequally short setae; ventrally with aesthetasc y1 (ca. 1/4 length of second endopodal segment) and aesthetasc y2 (reaching beyond middle of terminal segment). Third endopodal segment apically with three claws (G1, G2, G3) and three setae (z1, z2, z3). Terminal segment ( Fig 8C ) with two claws, one long (GM) and one slightly short (Gm), one aesthetasc y3 with accompanying seta (ca. 3x length of aesthetasc y3), and one g-seta, ca. 2/3 length of y3. Md-palp ( Fig 9A ) with four segments. First segment with two long plumose setae (S 1 and S 2 ), one long smooth seta and short slender smooth α-seta. Second segment with two dorsal unequally short setae; ventrally with stout hirsute β-seta (ca. 2/3 length of third segment) and four long setae (three hirsute and one smooth). Third segment with three groups of setae: dorsal group with four setae (three unequally long and one short, ca. 1/4 length of longest); lateral apical γ-seta (1/2 length of terminal segment) and three smooth short setae; one ventral group with one long seta with same length of terminal segment and one very short seta. Terminal segment with L ca. 3x basal width, with three unequally long claws and two short setae. Md-coxa ( Fig 8D ) elongated, dorsally with a short seta, and with strong and apical teeth, interspaced with some setae. Mx1 ( Fig 9B —chaetotaxy not complete) consisting of three masticatory lobes (endites), a two-segmented palp and a large branchial plate (not illustrated). Branchial plate elongated with ca. 16 respiratory rays, some quite short, others longer. First segment of palp with five unequally short setae and one stout plumose seta at base of segment. Terminal segment of palp rectangular, ca. half the length of first segment of palp, apically with three claws and two setae (one long 2/3 length of claws, and one short 1/3 length of claws). Third and second endite with two smooth claws. First endite short with two basal setae (one short and one long, about 4x length of previous one). T1 ( Fig 9C ) with protopodite apically with a group of 12 unequal and hirsute setae; two short smooth a-setae, one short smooth b-seta and one long and hirsute d-seta (ca. 6x length of b-seta), and one long and hirsute seta next to the two a-setae (ca. 2x length of d-seta). Endopodite apically with one long and two short setae (one ca. 2/3 length of the long and one 1/2 length of the long). T2 ( Fig 10A ) with protopodite, including a “knee”-segment and four endopodite segments. Protopodal segment without d1-seta. “Knee”-segment without d2-seta. First endopodal segment with one apical hirsute e-seta, reaching tip of second endopodal segment. Second endopodal segment with one apical hirsute f-seta, slightly shorter than third segment. Third endopodal segment with one subapical hirsute g-seta, reaching tip of terminal segment. Terminal segment with one short hirsute h1-seta, one hirsute h3-seta, slightly shorter than h1-seta and apically with one long, strongly curved and serrated h2-claw (ca. 2/3 the length of this segment). T3 ( Fig 10B ) with four segments. First segment with one long and hirsute ventral dp-seta and one short hirsute d1-seta, ca. 1/2 length of dp-seta, d2-seta missing. Second segment with one very short subapical e-seta. Third segment with two very short setae: medial f-seta and subapical g-seta. Terminal segment short, slightly longer than wide, with three hirsute setae: one short h1-seta, one h2—seta, more than twice the length of seta h1 and one very long h3-seta, about same length as T3. CR ( Fig 10C ) well-developed and robust, with long hirsute proximal Sp-seta (ca. half the length of ramus), subapically with shorter serrated Gp-claw, apically with long serrated Ga-claw and short and smooth Sa-seta. FIGURE 9. Brasilocypria pea gen. et spec. nov. ♀ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . Md-palp (MZUSP 43092). B . Mx1 (MZUSP 43092), stout plumose seta (MZUSP 43099). C . T1 (MZUSP 43092), long seta next to the two a-setae (MZUSP 43099). Scale bars: A–C = 50 μm. FIGURE 10. Brasilocypria pea gen. et spec. nov. ♀ from Upper Paraná River floodplain, Aurélio Lake (PAR 150). A . T2 (MZUSP 43092). B . T3 (MZUSP 43092). C . CR (MZUSP 43098). D . CR attachment (MZUSP 43092). Scale bars: A–D = 50 μm. CR attachment ( Fig 10D ) robust, with two branches: db short with a rounded protrusion distally and vb longer than db and without a protrusion. Remarks: As this species occurs in two distant floodplains, we also illustrated valves of males ( Figs 11 , 12 ) and females ( Fig 13 ) and carapaces of males and females ( Fig 14 ) from Upper Paraná River floodplain and South Matogrossense Pantanal to show potential variability amongst the specimens. For example, in males of the Upper Paraná River floodplain ( Figs 11A, C ), the LVi has a greatest height slightly behind the middle, while the greatest height is in front of the middle in specimens from Pantanal ( Figs 11E, G ) and in CpRl ( Fig 14A ). RVi has marginal tubercles only along the posteroventral margin in males from the Paraná floodplain ( Figs 11B, D ), and marginal tubercles along all of the ventral margin in specimens from Pantanal ( Figs 11F, H ). Females from the Paraná floodplain ( Fig 13D ) and Pantanal ( Fig 13F ) have marginal tubercles along the entire ventral margin in the RVi, or only from the middle to the posteroventral margin in both floodplains ( Figs 13B, H ). We also illustrate the outline of Hp and prehensile palps of four males that can show some variabilities between specimens ( Fig 15 ), e.g., some ms lobe of Hp are slightly less pointed ( Figs 15E–F, M–N ) than others ( Figs 15 A–B, I–J ). Also, Rpp ( Fig15C ) is more robust than in other specimens, while in Lpp the first segment can have either a wider ( Figs 15D, H ) or a more slender basal segment ( Figs 15L, P ). FIGURE 11. Brasilocypria pea gen. et spec. nov. ♁ A from: A–D = Upper Paraná River floodplain, Aurélio Lake (PAR 150) and E–H = South Matogrossense Pantanal, Carenda Forest Road, lake 1 (PAN 09). A . LVi (MZUSP 43094). B . RVi (MZUSP 43094). C . LVi (MZUSP 43093). D . RVi (MZUSP 43093). E . LVi (MZUSP 43101). F . RVi (MZUSP 43101). G . LVi (MZUSP 43109). H . RVi (MZUSP 43109). Scale bars: A–H = 250 μm. Arrow indicates anterior direction. B, D, F, H arrow indicates piths fitting teeth in opposing valve. FIGURE 12. Brasilocypria pea gen. et spec. nov. ♁ A from Upper Paraná River floodplain, Aurélio Lake (PAR150). A . LVi, posterior part (MZUSP 43094). B . LVi, anterior part (MZUSP 43094). C . RVi, anterior part (MZUSP 43094) arrow indicates piths fitting teeth in opposing valve. D . RVi, posterior part (MZUSP 43094). Scale bars: A–D = 100 μm. Ecology and distribution . Brasilocypria pea gen. et spec. nov. was recorded from two tropical Brazilian floodplains ( Paraná and Pantanal), associated with different species of macrophytes. The water temperature ranged between 21 and 26°C. The pH ranged from 5 to 7. The range of electrical conductivity was between 31.1 and 215 μS. cm-1 and the values of dissolved oxygen varied from 1 to 2.3 mg . L- 1 (see Table 1 ).